Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations (which only mark it non-read-only, open-world, non-idempotent): it discloses the returned artifacts (wallet code, ak_live_ API key, spend-only welcome credit), the credit's restrictions (eSIM data only; SMS numbers need a $1+ deposit), the auth header format for reconnection, and that passing acceptTos=true accepts the ToS on the user's behalf — a meaningful side effect not captured by the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core action and routed alternatives, with each sentence carrying actionable content. The 'no human, no browser, no account, no email, no KYC' chain and parenthetical credit caveats add length but each clause conveys a real constraint.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, and the description compensates by describing the return payload (code, key, credit) and how to use it. For a single-parameter creation tool this is nearly complete; only minor details like key handling security or key persistence are left implicit.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the schema already documents acceptTos, so the baseline would be 3. The description adds value by explaining the semantic consequence of the flag (agent accepts the ToS on the user's behalf) and tying it to the required creation step.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Create a NEW PikaSim agent wallet') plus its purpose (autonomous purchasing) and enumerates what it returns. It is clearly distinguishable from siblings like check_balance or purchase_esim, and it explicitly distinguishes create vs. reconnect.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit when-to-use ('when the user has NO wallet yet and wants their agent to buy') and when-not ('If the user ALREADY has a wallet, do NOT create a new one — reconnect the existing wallet instead'), including the fallback instruction to ask the user for the existing wallet.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.